Expansion bit



LssLloo R. E. DIAL EXPANSION BIT Nov. 10, 1931.

filed Nov. 5. 195o 2 Sheets-Sheet 1 Nov. 1o, 1931.

R. E. DIAL 1,83,l00

EXPANSION BIT 2 Sheets-Sheet 2 Filed Nov. 5. 1930 GMM/nui@ Patented Nov. 10, 1931 Unirse STATES PATENT/OFFICE ROBERT E. DIAL, or RosEDALn, INDIANA,` AssIGNoR or ONE-HALF To HERMAN In BRUNNER, or nosEDALn, INDIANA EXPANSION BIT i Application filed November By way of explanation, it may be stated that it is common in coal mines, to bore a hole for a charge of power, and this invention aims to provide a novel expansion bit, which, placed in the hole, can be expanded, so as to ream out a chamber at the inner end of the hole, thereby to enable the powder to be placed more advantageously for a shot.

The invention aims to provide a devi-ce of the class described having novel means for controlling the lateral movement of the side bits. It is within the province of the disclosure, moreover, to improve generally, and to enhance the utility of, devices of that type to which the invention appertains.

lVith the above and other objects in view which will appear as the description proceeds,

Athe invention resides in the combination and arrangement oi parts and in the details of construction hereinafter described and claimed, it being understood that changes in the precise embodiment of the invention herein disclosed may be made within the scope oi what is claimed without departing from the spirit of the invention.

In the accompanying drawings Figure 1 shows in side elevation, a device constructed in accordance with the inven-v tion;

Figure`2 is a longitudinal section wherein parts appear in elevation;

Figure 3 is a side elevation of the tool, the bits being contracted, instead of expanded as in Figure 1;

Figure 4 is an end elevation indicated by lthe line 4-4 in Figure 3;

Figures 5 and 6 are sections taken on the lines 5 5 and 6--6 of Figure 2.

The tool forming the subject matter of this application preferably is made of metal throughout. It comprises an elongated cylindrical body 1 provided with any desired number of spiral ribs 2. The body 1 has a rectangular bore 3 which is expanded at its rear end to form a socket 4 receiving the end 5,1930. serial No. 493,639(

is a recess 8 forming shoulders 9 and 10.V A 5 l stop pin 11 is mounted inthe body 1 and eX- tends across the bore 3, the. above said pin eX- Atending across the recess V8 of the center bit 6 between the shoulders `9 and 10. l l An abutment pin 12 extends across the bore 3 and is mounted in t 1e bodyy 1 somedistance behind the rear end of the center bit 6. Against the pin I 12, a lcompression spring -abuts, the forward end of the spring I15 engaging the rear end of the center bit 6. On its rear'end, the center bit has a iinger 16 engaged within' the forward end of the spring 15 and aiding in holding the spring in place.

The centerbit 6 is provided with a projection 17 in the formof a block, which extends around three sides of the center bit. The projection or block 17 is shown as being held in place by a securing element 18, but if desired, the projection' 17 and the center bit 6 may be formed inone piece, such a change "requiring no lspecific showing inthe drawings. At its forward end, the body 1 "has outstanding 'enlargements 19, and certain of these enlargements may be formed integrally `with the forward ends of the spiral ribs 2, 30 as shown in Figure 3. The enlargements 19 have slots V2O across which extend pivot elements 21. Side cutters 22 and 23 are mounted at their rear' ends in the slots 2O and'on the pivot elements 21, for'inward and outward radial swinging movement. The side cutters 22 and 23 may be beveled and sharpened at their forwardends, as shown at 26, although the cutting edges of the side cutters 22 and 23 may be formed in any desired man-l body, .on the body,

ner. Cams 24 are held on the side cutters .23 by securing devices 25, although the cams might be formed in one piece with the side cutters if desired. The side cutter 22 does not have a cam 24.

the spring 15 In practical operation,

until the forces the center bit 6 forwardly, shoulder 10 engages the stop pin 11. Under such circumstances, the side cutters 22 and 23 are swung inwardly, as shown in Figure 3, the side cutter 22 resting against the center bit 6, as shown in Figure 3, and the projection 17 being clear of the cams 24; on the side cut.- ters 23 so that the said side cutters can swing f inwardly.

When the point 7 of the'center bitf6 comes into contact with the inner end of the hole that has been bored, the center bit- 6 is shoved backwardly into the position of Figure2, the spring being compressed, and the shoulder ,f9'coming into contact with the stop pin 11. `As' the Vcenter bit 6 moves backwardly, the `projection or blockr 17 co-operates with the cams 24 on the sidecutters 23 and swings the side Vcutters 23 outwardly, the side cutter 22 remaining lin place near the sid-e edge of the center bit 6, as shown in lFigure 2 of the drawings. lThe cams 24 are so placed on the yside cutters `23 that the side cutters 23 will extend outwardly at different angles with.

respect to the center bit 6, the side cutter 22 being nearest to the center bit 6, the side cutters 23 extending outwardly at progressively increasing angles. The cutters 22 and 1 23,- therefore, cut one after another, to ream out and enlarge the hole at its inner end, as .the tool is rotated. After the hole has been reamed out to the desired extent, the tool can be withdrawn. As soon as there is yno pressure on the forward end of the center bit 6,

vthe center bit 6 isl shovedforwardly by the action of the spring 15, and then, the side cutters 22 and 23 can swing inwardly into approximate parallelism with thee-enter bit 6 as vshown in Figure 3, thereby permitting the tool to be pulled out of the hole.

The device is simple in. construction, but

it aifords means whereby a miner can ream 1 out a blast -hole readily. The `device form- -=1ng -respectto `the center bit, whenthe center bit moves rearwardly.

V2. In, Va device ofthe :class described, -a

body, a center bit mounted for reciprocation in the body, side cutters pivoted to the body, and relatively inclined parts on the side cutters and on the center bit, said inclined parts being so proportioned that, when the center bit moves rearwardly, the side cutters will be inclined outwardly at different angles with respect to the center bit.

In testimony` that I claim the foregoing as my own, I have hereto aiixed my signature.

ROBERT. DIAL.

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